Lecture on Building a Full Adder in Logisim

Introduction

• Host: Pika Cubed
• Topic: Building a full adder using Logisim
• Purpose: To teach viewers how to create a full adder circuit in Logisim and prepare for future videos on creating an 8-bit adder.

Setting Up the Project

• Save the project file:
  • Filename: 'adder'
  • Location: Desktop

Creating Inputs

• Inputs needed: A, B, and C (Carry-in)
  • Add pins for each input using the pin tool in Logisim.
  • Label pins as A, B, and C.

Adding Logic Gates

1. XOR Gate:

   • First XOR gate:
     • Inputs: A and B
   • Second XOR gate:
     • Inputs: Output of first XOR gate and C
   • Resulting output labeled as "Sum"

2. AND Gates:

   • First AND gate:
     • Inputs: A and B
   • Second AND gate:
     • Inputs: Output of first XOR gate and C

3. OR Gate:

   • Combine outputs from both AND gates
   • Result labeled as "Carry Out"

Connecting the Circuit

• Connect A and B to the first XOR gate.
• Connect the output of the first XOR gate and C to the second XOR gate.
• Connect A and B to the first AND gate.
• Connect the output of the first XOR gate and C to the second AND gate.
• Connect outputs of both AND gates to an OR gate.
• Label outputs: "Sum" and "Carry Out"

Testing the Circuit

• Use the poker tool to test:
  • Inputs: 1 and 1 should give a carry-out.
  • Inputs: All 1's should result in a sum and carry-out as expected.

Conclusion

• Successfully built a full adder in Logisim.
• Next steps: Enable viewers to daisy chain full adders into an 8-bit adder in future videos.